1. Field of the Invention
The invention relates to an oil-in-water suspoemulsion, the suspoemulsion comprising a major portion of water as a continuous phase, at least one water insoluble active, and an encapsulate comprising an oil, at least first and second nonionic surfactants, the first and second nonionic surfactants having a HLB of at least about 3. The encapsulate either protects the active from premature dispersion, activation or reaction, allows a greater loading of the active into the suspoemulsion compared with prior systems, protects the container for the suspoemulsion from the active, or a combination of the foregoing.
2. Brief Statement of the Related Art
A suspoemulsion is an oil-in-water emulsion which has been previously described in the art in the context of delivery systems for agricultural chemicals, such as herbicides and pesticides. See, e.gs., Frisch et al., U.S. Pat. Nos. 5,074,905 and 4,853,026, and Dookhith et al., U.S. Pat. No. 5,096,711. The use of suspoemulsion has not, however, been disclosed, taught or suggested for use in delivering cleaning, laundering or household surface treatment products.
Additionally, EP 875557 (Rohm and Haas) discloses a thickening system for an aqueous composition in which two surfactants differ in their HLB characteristics by at least 1.0, most preferably 6.0 units, and which are combined with a hydrophobically-modified polymer associative thickener. The thickening systems are apparently produced in advance of addition to aqueous formulations, resulting in a solvated xe2x80x9csurfactant-thickener matrixxe2x80x9d (page 8, line 47), which, when added to an aqueous formulation, results in a thickened reticulum throughout the aqueous formulation, allowing the suspension of various actives throughout the formulation because it has been so thickened. And, although these formulations are described as including cosmetic and personal care formulations and cleaning formulations (See page 13, lines 30-49), it is clear that the target executions of this invention are primarily coating compositions, such as paints and stains, where thickening of the formulations are crucial to prevent sagging and to facilitate leveling on surfaces to which the formulations are applied.
On the other hand, various efforts to protect sensitive actives in liquid, aqueous cleaning or laundering formulations have also been heretofore described. For example, in Haendler, U.S. Pat. Nos. 5,075,029 and 4,929,383, a liquid hypochlorite bleach contains actives, such as ultramarine blue (UMB), which are suspended in a latex reticulum to prevent premature release into wash water and premature oxidation by the hypochlorite in which the UMB is suspended. The latex reticulum is described as having a lipophilic phase for polymer droplets of submicron size. However, this latex reticulum is composed of either oxidized polyethylene, polyethylene-acrylic acid copolymer, or mixtures thereof, which differ markedly from the surfactant encapsules of the invention.
Further, in Koerner et al., U.S. Pat. No. 5,589,448 and Sells et al., U.S. Pat. No. 5789,394, hydrolytic enzymes, common ingredients in cleaning formulations, have been suspended in a structured liquid comprising two different surfactants having a first HLB of greater than about 11 and a second having an HLB of less than or equal to 11, the difference in HLB values between the first and second surfactant exceeding about 2. Pointedly, in both references, hydrotropes, organic solvents and surfactants other than nonionic surfactants cannot be present or disruption of the structured liquid matrix in the liquid composition will occurs, resulting in a loss in enzyme stability
The invention provides an oil-in-water suspoemulsion system for the delivery of actives for laundering, cleaning or surface treatment, the suspoemulsion comprising a major portion of water as a continuous phase, at least one water insoluble active, and an encapsulate comprising an oil, at least first and second nonionic surfactants, the first and second nonionic surfactants having a HLB of at least about 3, the encapsulate substantially completely coating the active and suspending it within the aqueous phase.
It is therefore an object of this invention to provide an oil-in-water suspoemulsion for the delivery of actives for laundering, cleaning or surface treatment, the release of actives typically occurring in an aqueous wash water, or by application to a surface, with abrading action.
It is a further object of this invention to provide in the suspoemulsion an encapsulated active, which either protects the active from premature dispersion, activation or reaction, allows a greater loading of the active into the suspoemulsion compared with prior systems, protects the container for the suspoemulsion from the active, or a combination of the foregoing.
It is also an object of this invention to provide a suspoemulsion formulation which can deliver a cleaning, oxidizing, fragrancing, antimicrobial, fabric softening, brightening, shining, restorative, anti-staining or other functional or aesthetic performance.